Effects of urban geometry and green area on thermal condition of urban street canyons in Bangkok

ABSTRACT

Urban geometry and green area have a great impact on urban heat island intensity (UHII) in Bangkok. The current study focuses on 1) effect of height-to-width (H/W) ratios of street canyon on increasing UHII; and 2) percentage of tree coverage and non-tree coverage area, the surface temperature of pervious and impervious surfaces, and the surface temperature of planting materials. The night-time investigation to indicate the UHII influenced by H/W ratio was done with car traverse. UHII magnitudes were 6.33 K, 6.70 K and 4.54 K for the days representing rainy season, winter, and summer, respectively. Results from the daytime investigation to study green area effect show that surface temperature varies according to percentage of pervious surface area. With combination of tree coverage area, surface temperature will be decreased more. The optimum surface temperature was found when pervious surface was around 60% and tree coverage was around 25%.

KEYWORDS:

• Thermal condition
• urban geometry
• urban street canyon
• green area
• surface temperature
• tree shading
• Bangkok

Disclosure statement

No potential conflict of interest was reported by the authors.